ES : Electrical Hazards

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Chapter : Electrical Safety

Electrical Hazards 

Electrical hazards are doubly hazardous in that there is not only the chance of electrocution but also, there is the probability that any electric shock will cause a loss of consciousness that may well result in a fall of some sort. Today we will discuss methods of receiving an electric shock and ways to avoid electrical hazards.

Almost any kind of job you can think of today involves using electricity. That is why it is important for everyone to understand how to avoid electrical shock. 

There are many different kinds of electrical hazards, depending on the kind of place where you work. Some job sites have high voltage installations and some use small electrical equipment. But whether the electrical shock comes from an overhead (high voltage) transmission line or an incorrectly grounded power tool, the results can be equally fatal.

Besides electrical shock, electricity can also cause other hazards.

1. Electrical shock can cause the startled victim to fall from a ladder.
2. Electricity causes burns, including severe internal burns.
3. Electricity can cause fires, for instance when circuits are overloaded and the resulting heat sets off a fire.
   
4. Electricity can cause explosions, as would be the case if an electrical spark occurred in presence of a flammable vapor, gas or dust.

When electricity enters the human body, it can affect the heart beat, brain function and breathing. It can cause immediate death or serious injury. Under adverse conditions, even small amounts of electricity can kill a person. So never take any electrical device for granted.

Methods of Receiving an Electric Shock

• From a defective power tool.
• From defective extension cords.
• From overloading a switch or over-riding a by-pass.
• By not grounding electrical equipment.
• By coming in close contact with live electric lines.
• By coming too close to high power lines with the power arching over and making contact.

Ways to Avoid Electric Hazards

• Always inspect tools and equipment for frayed cords and defective plugs before using them.
• Never use a power tool that has had the ground plug removed; inspect the plug.
• Never stand in water and operate a power tool without proper (i.e., insulated) footwear.
• Keep extension cords out of water when in use.
• Consider all power lines “live” and avoid contact with them.
• Follow the company assured grounding/electrical protection program.
• Disconnect all electrical tools and cords when not in use.
• Be use all temporary lighting is equipped with bulb covers.
• Make sure all power supplies, circuit boxes and breaker boxes are properly marked to indicate their purpose.
• Use Ground Fault Interrupters (GFI’s) on all jobsites.

Extension cords/Power Strips

• Extension cords should not be used in place of permanent wiring.
• Ensure that cords are in proper working condition (the outer insulation should not be cracked/broken, the ground pin needs to be intact). Discard unsafe extension cords.
• Only licensed electricians are authorized to replace plugs, or splice cords.
• Extension cords need to be protected from motor vehicles, fork lifts, pallet jacks, heavy pedestrian traffic, etc.
• Power strips should not be permanently mounted to a wall or any other structure, even if the power strip has specific mounting fittings.
• Power strips or extension cords should not be connected to each other. Doing this can overload the circuit creating a potential fire hazard.

Circuit Overload Protection Devices:

These devices are designed to protect the wiring in a house/building and to prevent a potential fire.

Fuses- Break the circuit when too much current is flowing through the circuit. A small conductor inside the fuse heats up and melts when it reaches a specific temperature.

Circuit Breakers- As current increases in the circuit, an electromagnet inside the breaker generates increased magnetic force, eventually being great enough to pull the switch on the breaker from the “on” to the “off” position.

Ground Fault Circuit Interrupters

• GFCIs are designed to protect people from an electric shock.
• A GFCI works by detecting a current drop from the hot to the neutral wiring in a circuit. The GFCI detects energy that is escaping the circuit.
• GFCIs should be installed wherever a water hazard is present.
• You will commonly find GFCI plugs on hairdryers, wet vacs, etc.
• GFCIs can be at the breaker, the outlet, incorporated with the plug of the appliance/piece of equipment, or part of a short extension cord.

Short circuit arcing faults
 
Short circuits occur when conductors come in contact with an electrical circuit.
Metal screwdrivers, wrenches, and test instruments are examples of conductors.

A short circuit can lead to unimpeded arcing (a discharge of electricity through gas or air) until a circuit breaker, fuse or ELCB opens the circuit. But even if the circuit is opened, portions of the conductors or nearby metallic materials in path of the arc can explode. This can shower the area with hot molten metal that can penetrate clothing and the body and can cause severe burns. Flashing associated with an arc can cause permanent eye damage. To protect yourself, always switch the power off before working on electrical equipment.
 
Points to be checked prior to use of electrical equipment:

1. All electrical equipment must be in good condition, and inspected prior to its use. Explain the probable common defects, which to be looked for during inspection.
2. The plugs on electrical devices must have good prongs without any crack. The electrical cords must not be frayed / exposed / taped. All electrical joints shall be made with proper plugs and sockets.
3. Electric cords must be kept away from water and crude oil. Electrical cords must also be protected from fraying when being used on platforms, laid over railings, etc
4. Portable electric tools should be double insulated. Double insulated tools have plastic housings. Portable power tools with metal casings have only single insulation and must be grounded prior to use.
5. Electric devices must be de-energized and locked out before commencing any work. The inspection & repairing of electrical devices must be performed by a certified electrician.
6. Temporary wiring must conform to industry standards. Placing bare wire into outlets is strictly prohibited.

If Possible get a defective extension lead or electric power tool to display / point out the faults.

Follow these tips to avoid electrical shock:

• Always make sure all electrical equipment you use is in good condition. Report any problems, so the equipment can be repaired or replaced.
• Never do repairs on electrical equipment unless you are both authorized and qualified to do so. Fatal accidents have been caused by poorly repaired equipment.
• Use only correctly grounded equipment. Never use three-pronged cords which have had the third prong broken off. Make sure grounding connections are secure.
• Watch for wires and connections, which are damaged, worn or broken.
• Use a Ground Fault Circuit Interrupter (GFCI) / ELCB when using electrical equipment outdoors or in a damp area. Do not use electrical equipment which is damp or which may have been merged in water. Do not handle any electrical equipment, including cords and plugs, with wet hands.
• When unplugging a cord, pull on the plug rather than the cord.
• Never use a ladder made of aluminum or one with metal reinforcement when doing any electrical work. This includes changing a light bulb.
• Determine if there are any overhead hazards such as power lines and electrical installations. Take precautions when using ladders, poles or pipes so as to avoid contacting overhead or live electrical lines.
• Don’t ever use water on an electrical fire. Use only an extinguisher designed specifically for electrical fires (CO2 type fire extinguishers). Know where to locate and how to use this extinguisher in your workplace.

Always be alert to electrical hazards, no matter what kind of work you do. Be sure to use electrical safety sense at home too.